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Clarification on ESM Date: 2020/09/11 03:48 Name: Mauro Sgroi   <mauro.sgroi@crf.it> Dear all, I'm writing to ask for a clarification about ESM. Using it with a graphene monolayer with the a 6x6 supercell: Atoms.UnitVectors.Unit Ang <Atoms.UnitVectors 14.754317305999999 0.000000000000000 0.000000000000000 -7.377162205000000 12.777619736000000 0.000000000000000 0.000000000000000 0.000000000000000 20.000000000000000 Atoms.UnitVectors> I get the following error: <ESM:Warning> The b- and c-axes of the unit cell used for the ESM calculation must be orthogonal to the a-axis. I'm using ESM.switch on1 ESM.buffer.range 2.0 ESM.direction z So, has the cell to be orthorombic to use ESM? Thanks a lot in advance and best regards, Mauro Sgroi. Centro Ricerche FIAT Italy

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Re: Clarification on ESM ( No.1 ) Date: 2020/09/11 12:16 Name: Naoya Yamaguchi Hi, As the warning says, you have to set the a-axis orthogonal to the b- and c-axes. "ESM.direction" seems to choose a Cartesian axis for the ESM direction, not a cell axis. So, the a-axis is always taken as a special axis for the ESM, and you may avoid it by <Atoms.UnitVectors 0.000000000000000 0.000000000000000 20.000000000000000 14.754317305999999 0.000000000000000 0.000000000000000 -7.377162205000000 12.777619736000000 0.000000000000000 Atoms.UnitVectors> if the structure is the same as in http://www.openmx-square.org/forum/patio.cgi?mode=view&no=2677 Regards, Naoya Yamaguchi Re: Clarification on ESM ( No.2 ) Date: 2020/09/14 19:11 Name: Mauro Sgroi  <mauro.sgroi@crf.it> Dear Naoya, thanks a lot. I'm using ESM.direction z. So I was expecting to be able to use the c-axis instead of the a-axis. Is it not the case? Best regards, Mauro Sgroi. Re: Clarification on ESM ( No.3 ) Date: 2020/09/15 03:27 Name: Naoya Yamaguchi Dear Mauro, >So I was expecting to be able to use the c-axis instead of the a-axis. I also expected that, but the written source code was not true of it. Regards, Naoya Yamaguchi Re: Clarification on ESM ( No.4 ) Date: 2020/09/18 18:40 Name: Mauro Sgroi  <maurofrancesco.sgroi@gmail.com> Dear Naoya, thanks a lot! Can I ask a further clarification? I don't understand fully how to use ESM.buffer.range. I've a cell with an height of 30 Ang and a graphene monolayer at 7.5 Ang. The vacuum of the cell on top to will be filled with solvent molecules. Should I fix ESM.buffer.range to 30 Ang so that it covers the full supercell? Thanks a lot and best regards, Mauro. Re: Clarification on ESM ( No.5 ) Date: 2020/09/19 02:34 Name: Naoya Yamaguchi Dear Mauro, "ESM.buffer.range" is no longer active as I checked the source code. As such, you need to avoid overlap between PAOs and the ESM by checking all the atomic coordinates manually. >I've a cell with an height of 30 Ang and a graphene monolayer at 7.5 Ang. >The vacuum of the cell on top to will be filled with solvent molecules. You can use "ESM.wall.position" and "ESM.wall.height" to set barrier potential for restricting liquid molecules within a given region. Please take a look at "5. In case of MD calculations with the ESM method:" in http://www.openmx-square.org/openmx_man3.9/node151.html Regards, Naoya Yamaguchi Re: Clarification on ESM ( No.6 ) Date: 2020/09/20 05:33 Name: Mauro Sgroi  <maurofrancesco.sgroi@gmail.com> Dear Naoya, many thanks for the help. Best regards, Mauro Sgroi. Re: Clarification on ESM ( No.7 ) Date: 2020/09/24 18:33 Name: Mauro Sgroi  <maurofrancesco.sgroi@gmail.com> Dear all, I use this thread to ask a further question on ESM. If I want to simulate a charged electrode I've to use ESM.switch = on3 and set the charge using scf.system.charge. But I add solvent molecules all the supercell will be charged so I cannot simulate the fact that the charge is on the slab and that there is a potential difference between the solid and the electrolyte. Is there a way to proceed? Any published reference that can help? Thanks a lot in advance and best regards, Mauro Sgroi. Re: Clarification on ESM ( No.8 ) Date: 2020/10/07 23:26 Name: Mauro Sgroi  <maurofrancesco.sgroi@gmail.com> Dear developers, I discussed with Dr. Sugino the fact that in ESM it is possible to add a confinement potential to prevent electrons from leaking out from the conducting slab. This is described in the papers below: doi:10.1016/j.susc.2007.04.208 DOI:10.1143/JPSJ.77.024802 Is this functionality implemented in Openmx? Thanks a lot and best regards, Mauro Sgroi. Re: Clarification on ESM ( No.9 ) Date: 2020/10/08 13:12 Name: Naoya Yamaguchi Dear Mauro, Although I'm not the developer of the ESM function, as I checked the source code files, the artificial potential appears only in the calculation of atomic forces. There doesn't seem to be such a direct confinement potential for electrons, but OpenMX uses the numerical localized orbitals of PAOs as the basis set. So, I think that electrons may be naturally confined due to the cutoff radii of PAOs. Regards, Naoya Yamaguchi Re: Clarification on ESM ( No.10 ) Date: 2020/10/08 17:52 Name: Mauro Sgroi  <maurofrancesco.sgroi@gmail.com> Dear Naoya, thanks a lot for the clarification. Best regards, Mauro.

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